Resonant converters have many advantages over pulse-width modulated (PWM) converters due to their ability to achieve near lossless switching. This allows high switching frequency to be realized, thereby allowing miniaturization of the reactive components. Of voltage-type or current-type resonant converters, current-type topologies are the most advantageous because the primary switches achieve zero-voltage switching (ZVS), the rectifiers achieve zero-current switching (ZCS), and the capacitive output filter enables a fast response to load steps in highly dynamic applications. The most popular and most efficient current-type resonant converter is the series resonant converter (SRC). It has all the merits mentioned above, plus the lowest component count. This is especially true at high frequency where transformer leakage inductance may be used as the resonant inductor, thereby eliminating the need for a separate inductor.
However, despite these advantages, industry is reluctant to make the switch from PWM to resonant topologies, largely due to practical implementation issues that lead to increased size, and issues of control. Power conversion techniques currently employed in the design of information processing equipment therefore suffers from drawbacks including poor reduced-load efficiency and low power density.